Hechiza comes from the verb hechizar, which translates to 'to bewitch' or 'to cast a spell'.
In the song, Don Omar sings about "una sirena que hechiza" (a siren who bewitches), using this magical imagery to describe a mesmerizing woman on the beach who completely captivates him. It is a fantastic, poetic verb to learn for expressing an attraction that feels incredibly powerful and almost supernatural.
This song is a fantastic mix of heartbreak and party! Don Omar tells a story about an ex-lover who made him cry, but now the tables have turned. He sings, "Llorando se fue la que un día me hizo llorar" (Crying she left, the one who one day made me cry), and now she's the one full of regret, "recordando el amor / Que un día no supo cuidar" (remembering the love / that one day she didn't know how to care for). It's a classic revenge theme, but instead of moping, he's moved on.
How has he moved on? By heading to Brazil for a massive beach party! He sets the scene with "la luna, las estrellas / La playa, la arena / Para olvidarme de ella" (the moon, the stars / the beach, the sand / to forget about her). He finds a new woman, a "sirena que hechiza" (a siren that bewitches), and the rest of the song is a celebration of dancing with her. The track is built around the famous "Lambada" melody, and he invites you to feel the "Samba y calor" (Samba and heat) of the party.